Mrs May is just one of five senior ministers on the EU Exit and Trade (Negotiations) sub-committee, according to the latest list released by the Cabinet Office.

She is joined by Brexit Secretary David Davis and Mr Johnson - who were among the leading Leave campaigners in last year's referendum - and Chancellor Philip Hammond and Home Secretary Amber Rudd who were on the Remain side.

Last night sources close to Dr Fox said he had "not expected to be on the committee nor had he pushed to be on it" because it would have further prevented him from travelling. The source stressed that relations were good with his fellow ministers.